Freestanding liquid micro-optics

In this paper we report a novel alternative approach for creating liquid channel waveguides, by forming free-standing aqueous channels on a chemically modified metal substrate. These structures permit water to be used as the core of the waveguide, despite its low refractive index. This is advantageous for applications, such as optical sensing of analytes in aqueous solution, in which a strong overlap of the optical mode with the analyte is desirable. Furthermore the range of optical structures that may be formed is not restricted by the need for continuous laminar flow. We explore a range of optically significant shapes in which such micro-droplets may be sustained in air, and demonstrate optical guiding in water-cored channel waveguides.